in maverick, adding the following to the kernel command-line would allow console messages to be diverted to another system by means of a USB serial cable:
console=tty console=ttyUSB0,115200n8r
Attempting this with a 2.6.38-8-generic-pae kernel on natty results in a kernel panic (flashing caps-lock light on my T410 and no console output at all).
Same results on an Aspire One D260.
ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: linux-image-2.6.38-8-generic-pae 2.6.38-8.42
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic-pae 2.6.38.2
Uname: Linux 2.6.38-8-generic-pae i686
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Architecture: i386
ArecordDevices:
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: james 2753 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
Card hw:0 'Intel'/'HDA Intel at 0xf2420000 irq 44'
Mixer name : 'Conexant CX20585'
Components : 'HDA:14f15069,17aa214c,00100302 HDA:14f12c06,17aa2122,00100000'
Controls : 8
Simple ctrls : 5
Card1.Amixer.info:
Card hw:1 'NVidia'/'HDA NVidia at 0xcdefc000 irq 16'
Mixer name : 'Nvidia GPU 0b HDMI/DP'
Components : 'HDA:10de000b,10de0101,00100100'
Controls : 16
Simple ctrls : 4
Card29.Amixer.info:
Card hw:29 'ThinkPadEC'/'ThinkPad Console Audio Control at EC reg 0x30, fw 6IHT37WW-1.12'
Mixer name : 'ThinkPad EC 6IHT37WW-1.12'
Components : ''
Controls : 1
Simple ctrls : 1
Card29.Amixer.values:
Simple mixer control 'Console',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
Date: Tue Apr 26 14:45:28 2011
HibernationDevice: RESUME=UUID=67e3cd44-242b-4bbf-918b-28fff81e0312
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
MachineType: LENOVO 2516CTO
ProcEnviron:
LANGUAGE=en_GB:en
PATH=(custom, user)
LANG=en_GB.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic-pae root=UUID=7ad192e9-7b26-49d1-8e1c-fefc7dc495cb ro acpi_sleep=nonvs quiet splash vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-2.6.38-8-generic-pae N/A
linux-backports-modules-2.6.38-8-generic-pae N/A
linux-firmware 1.52
SourcePackage: linux
UpgradeStatus: Upgraded to natty on 2011-04-23 (2 days ago)
dmi.bios.date: 08/27/2010
dmi.bios.vendor: LENOVO
dmi.bios.version: 6IET72WW (1.32 )
dmi.board.name: 2516CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr6IET72WW(1.32):bd08/27/2010:svnLENOVO:pn2516CTO:pvrThinkPadT410:rvnLENOVO:rn2516CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 2516CTO
dmi.product.version: ThinkPad T410
dmi.sys.vendor: LENOVO
The problem appears to be confined to the scenario where the *only* specified console is a USB device:
# FAILS (when cmdline ends with):
console=
console=
console=ttyUSB0
console=
# WORKS (when cmdline ends with):
console=ttyUSB0 console=tty
console=tty console=ttyUSB0
(The bug title needs to be changed to reflect this).